1. Field of the Invention
The present invention relates to gasoline compositions effective for reducing intake valve deposits and which do not contribute to increased deposit formation in port fuel injected engines.
2. Description of the Related Art
It is well known to those skilled in the art that internal combustion engines form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports, and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. Deposits also form in the combustion chamber of an internal combustion engine as a result of incomplete combustion of the mixture of air, fuel, and oil. These deposits, even when present in relatively minor amounts, often cause noticeable driving problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Specifically, when the gasoline used in a given engine is of a constant octane number, the power output decreases when deposits are formed. In order to maintain the power output at a predetermined desired level, it then becomes necessary to increase the octane number of the fuel over the course of time. This Octane Requirement Increase (ORI) is undesirable. Therefore, the development of effective fuel detergents or deposit control additives to prevent or control such deposits is of considerable importance, and numerous such materials are known in the art.
Two general classes of additives are commercially known. One class comprises hydrocarbyl-substituted amines such as those prepared by reacting olefins and olefin polymers with amines (including polyamines). Typical examples of this class are polybutenyl amines. Another class of additives comprises the polyetheramines. Usually, these are "single molecule" additives, incorporating both amine and polyether functionalities within the same molecule. A typical example is a carbamate product comprising repeating butylene oxide units under the trade name "Techron.TM." marketed by Chevron.
In some cases, the polyetheramines are preferred as the oxygenation (from the polyether functionality) is thought to lower particulate matter and nitrogen oxide (NOx) emissions and combustion chamber deposits. In addition, polyetheramines require little or no additional fluidizer oil to pass certain industry mandated valve stick requirements, resulting in a more economical final package. Polyisobutenyl amines, on the other hand, do require the addition of fluidizer oil to pass valve stick requirements and in addition are perceived to cause higher combustion chamber deposits than the fuel alone.
U.S. Pat. No. 5,352,251, Lin et al., Oct. 4, 1994 discloses a fuel composition comprising cyclic amide alkoxylate additive compounds of the formula ##STR2## wherein x is from 2 to 20 and y is from 1 to 50. R.sub.1 and R.sub.2 are independently hydrogen or hydrocarbyl of 1 to 100 carbon atoms or substituted hydrocarbyl of 1 to 100 carbon atoms. R.sub.3 is hydrocarbyl of 1 to 100 carbon atoms or substituted hydrocarbyl of 1 to 100 carbon atoms and R.sub.4 is independently hydrocarbyl of 2 to 100 carbon atoms or substituted hydrocarbyl of 2 to 100 carbon atoms. R.sub.5 is hydrogen, hydrocarbyl of 1 to 100 carbon atoms or substituted hydrocarbyl of 1 to 100 carbon atoms or acyl of 1 to 20 carbon atoms. These compounds have been disclosed to be useful for decreasing intake valve deposits, controlling octane requirement increases and reducing octane requirement. The patent also discloses novel cyclic amide alkoxylate compounds.
U.S. Pat. No. 5,516,343, Su, May 14, 1996 discloses a polyetheramide deposit control fuel or lubricant additive having the formula ##STR3## wherein each R is independently H or an alkyl group containing from 1 to about 16 carbon atoms, wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently selected from the group consisting of H and lower alkyl groups containing from about 1 to about 4 carbon atoms, and wherein each R.sup.5 is independently a saturated or unsaturated hydrocarbon group containing from about 7 to about 22 carbon atoms, and wherein a+b ranges from 0 to about 80.
U.S. Pat. No. 4,081,456, Heiba et al., Mar. 28, 1978, discloses a compound having the structure: ##STR4## wherein the alkyl group has from 16 to 100 carbon atoms; R, R' and R" are individually selected from the group consisting of hydrogen, methyl and ethyl; and --N is the amino nitrogen of a lactam polyamine having the structure ##STR5## wherein m is an integer of 1 to 10 and R, R' and R" are individually selected as previously defined.
U.S. Pat. No. 2,945,863, Buc et al., Jul. 19, 1960, discloses amides of aminoalkyl pyrrolidones having the general formula ##STR6## wherein R represents at least one hydrocarbon group containing from 5 to 22 carbon atoms, R.sub.1 represents a member selected from the class consisting of hydrogen, lower alkyl and hydroxyalkyl of 1 to 5 carbon atoms, m represents a numerical ranging from 0 to 1 to 3 and n represents a positive integer of 2 to 3.